Spinal fixation systems may be used in orthopedic surgery to align, stabilize and/or fix a desired relationship between adjacent vertebral bodies and/or the occipital bone in the skull. Such systems typically include a spinal fixation element, such as a relatively rigid fixation rod or plate, that is coupled to a bone by attaching the element to various anchoring devices, such as hooks, bolts, wires or screws. The fixation element can extend between two bone regions to effect stabilization, positioning, reduction or fixation of the bones. The spinal fixation element can have a predetermined contour that has been designed according to the properties of the target implantation site and, once installed, the spinal fixation element holds the bones in a desired spatial relationship, either until desired healing or spinal fusion has occurred, or for some longer period of time.
Occipital hooks and hook techniques in the prior art rely on positioning bone screws drilled through the skull bone as a method of fixation. However, the bone screws inserted through the occipital bone can damage the fragile occipital bone and/or fail to provide adequate bone purchase. The failure to provide adequate bone purchase, which may be due to poor bone quality as a result of damage, osteoporosis or other conditions, may cause the screw to slip relative to the bone. In addition, prior art occipital hooks do not accommodate for variations in the thickness of the occipital bone.